Typology of the Massifs of Surface Waters of the Lower Reaches of the Danube River Based on the Structure of Benthic Macroinvertebrate Communities

The results of a typological analysis of aquatic ecosystems in the Danube River Delta (the Ukrainian and Romanian parts) based on the taxonomic composition of benthic macroinvertebrate communities are given in the paper. The hierarchical clustering using the Morisita and Chekanovsky - Sorensen indices was applied to identify similarities among benthic macroinvertebrate communities in different types of water bodies. The analysis revealed distinct typologically homogeneous groups of water bodies reflecting common hydrological, geochemical, and biocenotic characteristics. An updated typology of surface water bodies and a codification of aquatic ecosystems in the lower reaches of the Danube River are proposed according to the national methodology and the requirements of the EU Water Framework Directive.